Hello all,
When my 1985 volvo 244GL gets going around 45mph in 3rd and 55mph in 4th I get some really extreme vibrations.

These vibrations are pretty much a constant except for at around 65+mph when it disappear once I stop giving it gas and when the clutch is in. There is also a sweet spot around 70mph were it doesn't vibrate much. Go 68 or 72 and it gets really bad again.

It seems to me to be coming from the back area buts so hard to be sure...My wheels are in pretty good shape. The bolts are on tight. My muffler squeks abit but I can still hear it and its still clamped / held perfectly.

Any ideas?

Thank you so much - Jutboy

 

Check the engine mounts,Trans mounts and Center driveshaft bearing and support.

 

Sorry to sound stupid but what am I looking for...what do bad mounts look like?

How about the bearings? I'm pretty good with mechanics but I'm no professional...thanks

 

You have solid rubber mounts. The metal cap looking things where the stud comes out of will break loose when they are bad.
The trans mount is also rubber. Check if any are broke. You can also try lifting the motor with a prybar and see if the mounts seperate. You will need to do it from underneath.

Jack up the back end and secure safely. With the car in neutral and turn the driveshaft. If it is bad the bearing will spin in the rubber support. If the support flops easy then that is bad as well.